RANDOM WALK

In this summer's ear-shattering movie excess, "Armageddon," a swaggering Bruce Willis and his team fly a shuttle mission against an earth-colliding asteroid.

In the far western suburbs, Thomas F. Droege, a semi-retired electrical engineer, is on his own asteroid hunt -- without the Hollywood heroics.

The 68-year-old senior engineer at Fermi National Accelerator Laboratory in Batavia, aided by a circle of enthusiasts who collaborate via the Internet, is methodically scanning and photographing the heavens in search of the errant space boulder.

Using computer chips designed for fax machines and telephoto lenses from a mail-order camera store, Mr. Droege's network has identified hundreds of variable stars and at least one supernova. (Mr. Droege builds the cameras himself and has given 23 of them away to people who've volunteered for the survey after seeing his Web site at www.tass-survey.org.)

He embarked on the project in 1994 after the comet Shoemaker-Levy 9 slammed into Jupiter -- raising the alarming prospect of a large object hurtling toward Earth. "After that, I basically set out to solve the earth-colliding asteroid problem," says Mr. Droege.

"I know it's out there," he adds.

He began tinkering in his workshop with lenses and circuit boards. The result: a computerized telescope/camera he calls "Mark III."

Using this camera, Mr. Droege's network has taken an estimated 10 million measurements on 200,000 stars.

To track and catalog those observations as well as to design future sky-scanners, Mr. Droege recruited programmers on the Internet.

The group calls itself the Amateur Sky Survey, though some members hardly qualify as amateurs. One helper, an insurance company programmer, has a degree in high-energy physics.

Another, Mr. Droege speculates, "is probably in the military-industrial complex" because his data-crunching is so sophisticated: "Every so often, he does something that would have to require the world's largest supercomputer."

Volunteer Arne A. Henden, research astronomer at the U.S. Naval Observatory in Flagstaff, Ariz., says Mr. Droege is hardly an amateur, either. "He does have a good reputation in the field of electronics," Mr. Henden says.

During Mr. Droege's 25 years at Fermilab, he helped design electronic components for the instrument that found the last of six formerly hypothetical subnuclear particles called quarks.

As for a killer asteroid, Mr. Droege doesn't lie awake nights worrying: "My real goal is to have fun."